Tim,
I was just about try ESB 4.7 but since you are having the same problem with both ESB 4.7 and ESB 4.8, I guess I'll try another path.
Speaking of path, I also saw those threads that tackled this from the classpath angle - I also had the same results as you. I wonder if there is something with the jbossesb-properties.xml file that is creating havoc.
Anyway, thanks for joining!